Vehicle brake



J. MADDEN VEHICLE BRAKE Filed 0st. 21. 1927 5 Sheets-Sheet l I N V EN TOR.

A TTORNEY. I

Dec. 30, 1930. E. J. MADDEN 1,786,912

' VEHICLE BRAKE Filed Oct. 21. 1927 s Sheets-Sheet 2 46 .1 Ta APPI) 5mm; 40 1a 4o 44 4 48 0 8 If a0 /2 L I I: ,Q) i

' INVENTOR.

ATTORNEY.

E. .1. MADDEN Dec. 30, 1930.

VEHICLE BRAKE 3' Sheets-Sheet 5 AWHHH u INVENTOR.

ATTORNE lie between plates 20 forming thebalancer Patented l) ec. l I V i 4 UNITED STATES PATENT oFFIcE Application. filed Dotoher 21, 1927. Serial Roi 227,?12.

The present invention relates to vehicle and secured thereto by the'pins 21 passbrakes andmore especially to the so-called ing through the plates and eyes. Plates hydraulic brakes, though certain features are pivoted to link lfi'bymeans of pin' 22 thereof are also applicable to mechanically. which passes therethrough and through the k 5 operated brakes. I tongue 23 on the link. Immediately in 55 Heretofore in four-wheel brakes'ior vefront of the balancer 15, the link 16 is prohicles, if of the hydraulic type, when a leak vided with a wide shoulder 25 which preoccurs in the system, all of the brakes bevents more than a very limited movement of come inoperative, and, if of the mechanical the balancer 15 for a purpose to be described.

0 type, when one brake becomes disconnected, Each cylinder (10 or 11) consists of a cylto the three remaining brakes become a dangerinder barrel screwed into or otherwise conous combination. nected to a head member provided with Among the objects of the present invenside outlets into which are screwed branch tion therefore is to overcome these very seriing nipples 31 and 31a having tubes 32 and 15 one detects and thereby very greatly increase 32a connected thereto and leading each to Mr the safety of the braking system. one of the brakes. This head member 30 is i A further object is to improve the autofurther provided with a flange 33 by means matic replenishing of the liquid in the by of which it may be mounted securely. draulic system. c There is also an extension 34-. coaxial with 1 29 I A further object is to decrease the tendeach cylinder and bored out as at 35. s 7 ency of certain parts of the system to leak. In each cylinder isa piston connected by a Still other objects will readily occur to ball and socket joint 40 to a connecting rod those skilled in the art upon reference to the 12. These pistons consist ofa body portion following description and accompanying 41, including the socket ofjoint 40, and pro- 25 drawings in which vided with a skirt portion 42 at its outer end. 7

Fig. 1 is a ban view of the master cylin-r The inner end of body 41 terminates in a reders of a hyd i'aulic type of brake; duced threaded shank 43. having a narrow Fig. 2 is a side view of the same and the shoulder 44 at the end of the threads and has reserve tanks with one ofthe cylinders and a wide shoulder 45 of somewhat smaller 39 one of the tanks in vertical section; diameter than the main body. Upon shank Fig. 3 is a diagrammatic view in side ele- 4:3 is screwed a cylindrical nut 46 and a rubber vation showing one of theprinciples of the cup47 is held on shoulder l5 by means of invention as appliedto mechanical brakes; this nut. r V

Fig. 4 is a plan view of the same; The nut 46 and shankl3 are so propor- 35 Fig. 5" is a transverse vertical section tioned that'when screwed together the inner through one of the equalizers, therefor; surface of the two is substantially smooth Fig. 6 is a view from the right of the parts and against such surface is placed a second shown in Fig. 5, and 7 V I I rubber cup 48, complbtingthe piston and ren- Fig. 7 is a partial section of one oi'th'e dering it liquidtightin both directions. a

brake cylinders. r v In order to maintain cup 478 tightly a ainst V As indicated in Figs. 1, 2 and 7 the hy; thepiston proper and in order to limit t e indraulic' system comprises a' pair of master ward stroke of the piston so that the cup 48 cylinders 10 and 11 the pistons of which are can not; pass out of thecylinder 10 (or 11), a

operable by. the piston rods 12 pivotally conspacing cup or thimble 50, of somewhat 7 nected'attheir outer ends to a balancer 15, smaller diameter than the cup,,is pressed which in-turn is pivotally connected to a against the cupby a spring 51 and a guide link 16, connected to the brake pedal 17 carrod- 52 secured to said cup prevents lateral riedon shaft 18. The piston rods .12 will displacement thereof and carries'the spring each be provided with aneye 19 adapted to 5,1.

The'rod 52 is grooved, as at 53, and slides loo into bore 35 of the extension 3 1 as a therefor, the grooves 53 permitting disp aced tive' to stem 68 limited ide liquid to escape into the cylinder pro er.

Refilling of the cylinders is provid dd for by providing a passage 60 from a cylinder into a small chamber 61 in the upper part of the head member 30. Into each chamber 61 is screwed a cap 62 to which is secured a nipple 63 connected to a pipe 64 leading to a reserve tank 65, one for each cylinder.

Each cap 62 is bored out and counterbored to provide a shoulder 66 and each chamber 61 is provided with an axial opening 67 leading into the bore 35 and in each opening 67 is the stem 68 of a valve. The valve stem 68 is beveled at its lower end 69 and rod 52 is reduced as at 70 and at the end of the reduced portion provided'with a cam surface 71 adapted to lift the valve upon movement of said rod into the extension 34. 4

Telescoping into the stem 68 is a second valve member 75 havin its movement relay a. pin 7 6 coacting with slots 77 in stem 68 while a light spring 7 8 tends to keep the member 75 at the upper limit of this relative movement. The upward movement of stem 68 is resisted by a spring 79 between its upper surface and a washer 80 seated on shoulder 66.

The structure of the reserve tank 65 is com parativcly simple. Each tank consists of a cylindrical cup with a central opening in its bottom through which passesthe nipple connectin pi e 64 and the inner end of the f nipple is ace to form a valve seat. Within the cup is a piston 86 connected to a piston rod 87 adapted to' extend out through the screw cap 88 and provided with a light spring 89 adapted to press down upon the piston. The under side of the piston is provided with a valve'surface 90 adapted to seat upon the uper end of nipple 85 and stop the 'fiow of liquid from the tank.

.It is prefered to provide each tank with an opening 91 to limit the amount of liquid in filling, thereby providing a space for the entrance of piston 86. y

The operation of the re-fillin means would seem to be obvious from the escription already given, but'itshould be noted that by means of the spring 89 a light pressure is exerted at all times on the reserve liquid and consequently, there is a positive flow from the tank 65 into the cylinder when the passage way is open, as it will be when-the piston 41 is at the outer end of'its travel. However, as soon as the piston 41 moves toward the right, as in Figure 2,.the cam surface 71 on the rod 52 immediately lifts the valve stem 68 and thereby lifts the valve member 7 5 to close ofi the passage at the lower end ofthe pipe 64 and prevent beck flow of liquid from the c linder tothe reserve tank. The valve .mem r 5 is permitteda certain relative movement with the stem 68 in order that it- 'operative. As stated above in the objects of the invenmay not require too accurate a proportioning of the parts and insure proper closing of the valve.

The installation which has been described with referenceto the hydraulic typeof brake permits the operation of one pair of brakes entirely independent of the other air in a f0ur-wheel brake system but provi es equal pressure on both systems as long as both are working correctly. A slight variation in ressure'in the two cylinders 10 and 11 will e taken up by the balancer 15, but if anything should happen to one pair of brakes so that it becomes inoperative, thebalancer 15, through its limited movement, permits the normal operation of the other pair of brakes and thereby makes for greater-safety than the conventional brake system. In fact, the present system rovides means whereb if all of the fluid lea s out of one side of t e sys.

tem, the other side will still be intact and tion, the same principle is applicable to mechanically operated brakes and a diagrammaticshowing of such mechanism is made in Figures 3 to 6 inclusive. F

In these figures, the frame of an automobile is indicated at 100 and the four wheels by 101.

Each front wheel is provided with a brake- 102 and each rear wheel with a brake 103.

The brakes 103 are shown as operated through links 104 in turnactuated by cross shafts 105. The cross shafts 105 are separate shafts and are aligned with their inner ends adjacent within a sleeve 106. This sleeve 106 has fixed thereto an arm 107 which through a link 108 is connected to the upper end of a lever 109 and through a link 110 connected to pedal 111. The lower end of the lever 109 is connected through alink 112 through a similar arrange ment to the front brakes 102. Referring to Figure 5, it will be noted that the shafts 105 have keyed to their inner'ends operating levers 115 which normally are in the same plane. The upper ends of these levers 115 are connected together by a rod 116 and where the rod 116 connects to the lever 115 isia ball joint 117. This rod 116 is located in the path of the arm 107 so that when the latter is moved it carries with-it the rod 116 and both arms 115, thereby-rotating shafts 105 and applying the brakes connected theretoa part or the disconnecting otzsome element,.

the other member of the pair-also becomes inoperative. In such case, the operator of the vehicle may proceed with comparative safety because the other pair of brakes remain in operative condition. y

Referring again to the hydraulic type of brake, Figure 7 shows a new form of brake cylinder which is particularly suitable for the 1 present system.

In this figure, a double cylinder 150 having its parts at an angle is located within the brake drum and adapted to actuate the brake bands against said drum (the band and drum not being shown); The cylinder consists of a header portion 151 having screwed therein the two cylinders 152. In each cylinder is a metal piston 153 adapted when moved to force outwardly the piston rod 154, for the application of the brakes. A boot 155 surrounding rod 154 and secured over the outer end of the cylinder by a ring 156 is provided to prevent entry of dirt.

l Vithin each cylinder 152 behind the piston 153 isa rubber cup member 160. This member consists of a cup portion with a'heavy flange 161 which is firmly held between the inner end of cylinder 152 and a suitable seat 163 in the header member 151. This cup 160 covers the liquid inlet 165 and is expanded by forcing in the liquid from the brake system and takes the place of the conventional rubber member movable with the piston.

. In Figure 7 thebleeder passage is indicated at 170 and the valve therefor at 171.

It should be noted that the piston guide rods 87 in tanks 65 may he graduated as shown, to indicate the amount of liquid remaining in eachreserve tank and thus furnish a visible'indication of the improper functioning of either pair of brakes when this occurs. Unequal quantities of liquid in the tanks would of course indicate a leakage of one side of the. system. Further, these tanks may be marked as indicated so as to show which pair of brakes is faulty.

Now having described the invention and the preferred form of embodiment thereof,

. it is to be understood that the said invention is to be limited, not-to the s ecific details herein set forth and illustrate ,butonly by the scope of the hereunto appended claims.

I 1. In hydraulic; vehicle brakes, a master cylinder, a piston therein, movable to actuate the brakes, a reserve tank, a conduit from close said valve during initial movement of said piston.

. .4. In hydraulic vehicle brakes, a master cylinder, a piston therein movable to actuate the brakes, a reserve tank, a conduit from said tank to said cylinder, means for forcing liquid to flow from said tank to said cylinder, a valve for closing, said conduit against liquid flow, means carried by said piston to actuate said valve to close said conduit during initial movement of said piston, a second valve in said conduit operated by said liquid forcing means and adapted to close said conduit when said tank is substantially empty. 5. In hydraulic vehicle brakes, a master cylinder, a piston therein movable to actuate .the brakes, a reserve tank, a conduit from said tank to said cylinder, means for forcing liquid to flow from said tank to said cylinder,

a valve forclosing said conduit against liq-- uid flow, means carried by said piston to actuatesaid valve to close said conduit during initial movement ofsaid piston, a second Valve insaid conduit operated by said liquid forcing means and adapted to close said conduit when said tank is substantially empty, said forcing means being provided as the means to indicate the amount of liquid in said tank. EDWARD J. MADDEN.

said tank to said cylinder, means for causing i a flow of liquid from 'saidltank to said cylinder, and a valve actuated'bysaid piston to close said conduit with the initial movement of said piston,fsaid means including a valve for closing said conduit when said tank is substantially empty.

2. In hydraulic vehicle brakes, a master I cylinder, a piston therein, movable to actuate the brakes, a reserve tank, a conduit from said tank to-said cylinder, means for-causing a flow of liquid from said tank to said cylinder, and a valve actuated by said piston to close said conduit with the initial movementof saidpiston, said means including a spring 

